Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Fri, 24 May 2019 at 07:57, Colin Smale  wrote:

> Is the Jewish calendar in active use?
>

By followers of Judaism.  A lot of their holy days are based upon
luni-solar calculations.
As is Easter (and other movable Christian feasts).   The Islamic calendar
has a lot in common
with the Judaic calendar.

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Fri, 24 May 2019 at 01:45, Kevin Kenny  wrote:

>
> 'easter' suffices for the entirety of the Christian calendar[1].


Really?  So the Catholic (Western) and Orthodox (Eastern) churches have
reconciled
their calendrical differences?

Admittedly, if you know which religious definition of Easter applies in a
country you wish to
place a long-distance phone call to, you'll be able to figure out if
anybody is going to answer.
Otherwise, it can be confusing.

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Phake Nick]

Ah, and about the Chinese calendar leap month I mentioned a while ago, it
seems like some algorithm nowadays would tweet those leap month as negative
values, for instance if it is the 8th month that get leaped, then it could
be computationally represented as Lunar month -8.

在 2019年5月24日週五 14:57，Colin Smale  寫道：

> Is the Jewish calendar in active use? I recall it has an extra month every
> few years, and rules about months not starting on a Monday or something
> like that. Might be a nightmare for opening_hours.
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Colin Smale]

Is the Jewish calendar in active use? I recall it has an extra month every few 
years, and rules about months not starting on a Monday or something like that. 
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Phake Nick]

then again, what about month numbering in Chinese calendar? There are no
month name, only lunar month 1, lunar month 2, etc.

在 2019年5月22日週三 20:33，Paul Allen  寫道：

> On Wed, 22 May 2019 at 09:16, Rory McCann  wrote:
>
>>
>> I don't know much about the islamic calendar. Could you give some
>> examples of what data you'd like to enter? Most "opening hours" don't
>> need to include years, so is that a problem? You could just use the
>> islamic calendar month names if needed.
>>
>
> The problem with that is the same problem as allowing every language on
> the planet to
> use their own abbreviations for month names.  Only worse.
>
> For better or worse, we standardized on three-letter abbreviations for
> English month names.  We
> couldn't have gotten away with one- or two-letter abbreviations because
> then there would have been
> collisions: "M" could be March or May, "Ma" could be March or May, etc.
> Allow abbreviations in
> other languages using the Latin alphabet and you get collisions even with
> three-letter
> abbreviations.  So we use English abbreviations, applications are free to
> translate them
> into the user's own language.
>
> The problem is possibly fixable by switching to month numbering.  It
> doesn't make the translation
> aspect much easier since most modern programming languages can handle
> hashes (aka
> dictionaries, aka associative arrays) so there's no gain there.  It makes
> human comprehension
> harder, because many people have difficulty mentally translating month 8
> to August, so there's
> a disadvantage there (for those with English as a first language; for
> others it would probably
> be an advantage.  It would require editor support (not impossible) and a
> mass edit of
> the database (not impossible, especially as there's a guaranteed
> one-to-one correspondence).
> I don't see OSM making the switch to numeric months, because it's a lot of
> change for little
> gain, but I could be wrong.
>
> Now we throw in the Islamic calendar.  Which is luni-solar.  It's based
> around the phases of the
> moon, and there is not a one-to-one correspondence you get between, say,
> December and the
> Welsh Rhagfyr.   In the Islamic calendar, each month can be 29 or 30 days
> long, depending upon
> the visibility of the moon.  Except for the Shia Ismali Muslims, where
> odd-numbered months have
> 30 days and even months have 29 days.  I've neglected leap year handling
> for simplicity.  Then
> there's the Judaic calendar, which is similar in some ways to the Shia
> Islamic one, except it
> is prone to fiddling month lengths to avoid holy days falling on certain
> days of the week.
>
> Is this a real problem?  MARchesvan in the Judaic calendar is a collision
> with MARch, so we'd
> have to switch to 6-letter abbreviations.  The Islamic calendar has
> Rabi-Al-Awwal and
> Rabi-Al-Thani; Jumada-Al-Awwal and Jumada-Al-Thani; Zul-Qaadah and
> Zul-Hijjah, so that
> would need some though (are RAA, RAT, JAA, JAT, ZUQ ZUH acceptable?).  Or
> we switch to
> month numbers, remembering that Julian month 6 is not Islamic month 6 or
> Judaic month 6
> and that Shia Islamic month 6 isn't (quite) Judaic month 6 and that you
> have no idea which
> calendar is in use, just that it's month 6 in some unspecified calendar.
>
> There are other calendar systems out there.  Parts of the world still use
> the Julian calendar,
> which is currently 13 days ahead of the Gregorian calendar.
>
> As others have pointed out, we might be able to accommodate holidays.
> Although we're likely
> to end up with collisions in the two-character namespace we currently
> allow for them.  Feasible,
> maybe.  Month names are something that isn't feasible without namespacing
> opening_hours.
>
> Oh, and then there's the fact that days start at midnight in the Gregoran
> calendar but start at
> sundown in Islamic and Judaic calendars.  And some countries are on solar
> time, which
> can be up to 14 minutes behind or 16 minutes ahead of local mean time.
> Right now we
> assume that times are in the local timezone and that the timezone is
> offset by a known amount
> (usually a multiple of one hour, sometimes a multiple of 30 minutes or
> even a multiiple of
> 15 minutes) from UTC, not that local time drifts around.  If people want
> to specify times as
> solar time, because that's what their country uses, we again need to
> namespace
> opening_hours.
>
> And don't forget that whatever we come up with has to work in conditional
> statements.  So we
> can have major changes to opening_hours that will require support in
> editors and applications
> and will probably have problems that we only discover down the line or we
> namespace the
> opening_hours to keep things simple and to prevent a problem in one
> affecting all of them.
>
> --
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Kevin Kenny]

On Wed, May 22, 2019 at 10:10 AM Simon Poole  wrote:
> That is not really correct as written, OH has the concept of variable dates 
> which are based on some external definition of when they exactly are, 
> currently the only one defined is "easter".  Typically you would use these to 
> start/end date ranges or a single date that is on or can be defined relative 
> to such a date. So adding "ramadan" or any other, externally defined date of 
> note is not really an issue as long as the string used doesn't conflict with 
> anything else.

'easter' suffices for the entirety of the Christian calendar[1].  All
of the movable observances, from Septuagesima to Corpus Christi
(including well-known ones such as Ash Wednesday, Good Friday,
Ascension Thursday and Pentecost) are specified as a particular number
of days before or after Easter.

I'd be fine with adding such things as Ramadan, Eid al-Fitr, and
Muharram to the schema. Since it's easiest to consider fixed points of
the calendar, Hilal ar-Ramadan would most likely be the anchor point
for Laylat al-Qadr. Eid al-Fitr would have to be a separate point,
since it's determined by its own astronomical observation. (Ramadan
runs an extra day in most localities if clouds prevent the observation
of Hilal as-Shawwal.)

[1] Strictly speaking, the Feast of St Leander - a minor observance -
also is variable, observed on 27 February in common years and 28
February in leap years. This inconsistency arises because in the Roman
calendar, the days counted from the *end* of the month, and Leap Day
was done by repeating the _sextilis_ of February. (A leap year may
still be called a 'bissextile' year.) As far as I know, he's the only
saint on the modern calendar to have been martyred in the last five
days of February of a leap year. But I don't know of anything whose
opening hours are tied to the Feast of St. Leander. There's also a
complicated set of precedences and special cases for when movable
observances collide with fixed ones (e.g. what happens when Good
Friday falls on the Feast of the Annunciation), or when certain fixed
obervances fall on a Sunday, but I haven't heard any call to model
those, either.

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Graeme Fitzpatrick]

On Thu, 23 May 2019 at 22:27, Andy Mabbett 
wrote:

>
> If only there was some sort of ISO standard for representing dates...
>

Yep, especially when you get those pesky Americans involved :-)

Is 5/6, the 5th of June or the 6th of May?

Thanks

Graeme
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Andy Mabbett]

On Wed, 22 May 2019 at 13:31, Paul Allen  wrote:

> The problem with that is the same problem as allowing every language on the 
> planet to
> use their own abbreviations for month names.  Only worse.
>
> For better or worse, we standardized on three-letter abbreviations for 
> English month names.
> opening_hours to keep things simple and to prevent a problem in one affecting 
> all of them.

If only there was some sort of ISO standard for representing dates...

-- 
Andy Mabbett
@pigsonthewing
http://pigsonthewing.org.uk

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Philip Barnes]

On Thursday, 23 May 2019, Paul Allen wrote:
> On Thu, 23 May 2019 at 00:06, Graeme Fitzpatrick 
> wrote:
> 
> >
> > But what are Christmas & Easter if they're not religious holidays? :-)
> >
> 
> Not all religious holidays are created equal.  Many cafes and restaurants
> in tourist areas are
> closed on Christmas Day/Boxing day but are open on Good Friday/Easter
> Monday.
Easter Monday is not actually a religious holiday, its only the day off in-lieu 
of Easter Sunday being a none working day.

Good Friday in the Midlands at least is not equal, many businesses such as many 
factories are open and buses run a normal service. There are no buses here on a 
normal bank holiday Monday.

Phil (trigpoint) 

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Thu, 23 May 2019 at 00:06, Graeme Fitzpatrick 
wrote:

>
> But what are Christmas & Easter if they're not religious holidays? :-)
>

Not all religious holidays are created equal.  Many cafes and restaurants
in tourist areas are
closed on Christmas Day/Boxing day but are open on Good Friday/Easter
Monday.

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Graeme Fitzpatrick]

On Thu, 23 May 2019 at 00:10, Simon Poole  wrote:

> (I suppose there might be a use case for "RH", religious holidays, but
> lets don't add baggage before somebody actually asks for it :-)).
>

But what are Christmas & Easter if they're not religious holidays? :-)

Thanks

Graeme
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Rory McCann]

On 22/05/2019 14:31, Paul Allen wrote:

The problem with that is the same problem as allowing every language
on the planet to use their own abbreviations for month names.  Only
worse.


I'm not proposing that, I suggest we create a (short) list of accepted
calendar systems, and accepted abbreviations for each month in that
calendar. We don't have to expand it to all languages (you're right, it
would very impractical).

"Show in other languages" doesn't solve the problem of the months not
matching up.

Is this a real problem?  MARchesvan in the Judaic calendar is a 
collision with MARch, so we'd have to switch to 6-letter 
abbreviations.  The Islamic calendar has Rabi-Al-Awwal and 
Rabi-Al-Thani; Jumada-Al-Awwal and Jumada-Al-Thani; Zul-Qaadah and 
Zul-Hijjah, so that would need some though (are RAA, RAT, JAA, JAT, 
ZUQ ZUH acceptable?).


I'd leave it up to people familiar with the area to come up with good
abbreviations. I'm sure they already have recognizable abbreviations.

`opening_hours` is machine readable, but it's also (mostly) human
readable. If you put islamic/etc months in it, and a tool doesn't
support that, it can just display the raw tag text to the user who will
probably be able to read it and know what the opening hours are! By
putting data in `opening_hours` (not `opening_hours:islamic`) and using
local appropriate names, we retain that benefit. It degrades gracefully.


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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Rory McCann]

On 17/05/2019 21:13, Paul Allen wrote:
I think that you would have to come up with something like 
opening_house:islamic or something like that to segregate the two

systems.

There are some downsides to using a new `opening_hours:islamic` key:

 * What happens if there's an `opening_hours=*` and
`opening_hours:islamic=*` tag on the same object? And what if they are
correct?
 * Many OSM data consumers look at the `opening_hours` tag, and they
aren't aware of this new key.

I don't know much about the islamic calendar. Could you give some 
examples of what data you'd like to enter? Most "opening hours" don't 
need to include years, so is that a problem? You could just use the 
islamic calendar month names if needed.


So I suggest just adding the opening hours that would make sense for a 
local into the `opening_hours` tag, and follow the spirit of the 
opening_hours syntax.


--
R/A/McC


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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Saeed Hubaishan]

Adding ramadan as  is good.

I also  suggest adding optional [@calendar] to date range rules for non 
Gregorian dates and using month number instead of month abber name for example:

Sa-Th 09:00-21:00; 09/01-09/30 @hijri 20:00-03:00


الحصول على Outlook for Android<https://aka.ms/ghei36>


From: Simon Poole 
Sent: Saturday, May 18, 2019 1:59:39 PM
To: tagging@openstreetmap.org
Subject: Re: [Tagging] Opening hours syntax for non Gregorian calendar



As I've pointed out before the one thing that is unproblematic to add are more 
variable date public holidays, right now there is only easter defined,  adding 
ramadan for example would be no problem.

Further expressing a rule is one thing, evaluating it is a something else, and 
adding some kind of "context" value to help in the later (for example a time 
zone value as has been suggested previously)  could potentially work.

Simon

Am 18.05.2019 um 12:34 schrieb Phake Nick:
That doesn't seems to solve the problem that would occur. For instance, how to 
represent the first Sunday (a feature in Gregorian calendar) after Chinese 
traditional ceremony X (a feature in Chinese traditional calendar) in the 
opening time syntax, if they're split up for "simplicity"? What about when the 
opening time also cover non-holiday festivals that only occurs according to 
either calendars?

On 2019-05-18 Sat 04:50, Paul Allen 
mailto:pla16...@gmail.com>> wrote:
Problem of splitting: what if a mapper gives the opening times in both 
calendar_X and calendar_Y
and they disagree?  Consumers will have to have rules like: in country_Z use 
calendar_X if given,
otherwise use standard opening_hours if given, otherwise use calendar_Y if 
given, otherwise
pick at random from what is left.

--
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Simon Poole]

Am 18.05.2019 um 15:28 schrieb Paul Allen:
> ...
> Can we just ignore the problem?  For Easter, maybe.  Data consumers
> could build in
> country-specific rules defining if Easter is Orthodox or Catholic. 
> Along with astronomical
> calculations, that would allow an app to say "This office in a
> different country from you is
> closed because it follows a different definition of Easter from your
> location."  Not so easy
> for Ramadan defined by visual observation.
> ...

Evaluation of opening hours values already depends on location and lots
of configuration for the PH tag (and in principle for the SH one too).
So this wouldn't be introducing anything new. See
https://github.com/opening-hours/opening_hours.js#holidays



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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Sat, 18 May 2019 at 12:01, Simon Poole  wrote:

>
> As I've pointed out before the one thing that is unproblematic to add are
> more variable date public holidays, right now there is only easter
> defined,  adding ramadan for example would be no problem.
>

Syntactically, probably not a problem.  Calculation of the astronomical
events is well-defined.
Interpreting those events is not:  In some schools of Islam, calculation
suffices; in others
visual confirmation is required.  The two can (and often do) differ by a
day.  Possibly
solvable by having ramadan_x and ramadan_y.  Or just by ignoring the
problem and stating
that "ramadan" means local definition of Ramadan, whatever that happens to
be.

Note also that whilst opening_hours blithely defines "easter," the date on
which it falls
differs between the Catholic and Orthodox churches.  When a country
celebrates
Easter depends upon religious factors.

Can we just ignore the problem?  For Easter, maybe.  Data consumers could
build in
country-specific rules defining if Easter is Orthodox or Catholic.  Along
with astronomical
calculations, that would allow an app to say "This office in a different
country from you is
closed because it follows a different definition of Easter from your
location."  Not so easy
for Ramadan defined by visual observation.

A bigger problem, as I see it, is that cultures using the luni-solar
calendar often have days of
the week that begin at sunset, not midnight.  Especially important in
religious observances:
the Jewish Sabbath starts at sunset on Friday.  In the current scheme, "Su
off" is not strictly
necessary (it can be inferred) but to be fair to other cultures you'll need
to be able to specify
Sabbath (the obvious abbreviation has a clash) and similar days in other
cultures.

These are just the problems I know of.  I doubt that is all of them.

-- 
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Simon Poole]

As I've pointed out before the one thing that is unproblematic to add
are more variable date public holidays, right now there is only easter
defined,  adding ramadan for example would be no problem.

Further expressing a rule is one thing, evaluating it is a something
else, and adding some kind of "context" value to help in the later (for
example a time zone value as has been suggested previously)  could
potentially work.

Simon

Am 18.05.2019 um 12:34 schrieb Phake Nick:
> That doesn't seems to solve the problem that would occur. For
> instance, how to represent the first Sunday (a feature in Gregorian
> calendar) after Chinese traditional ceremony X (a feature in Chinese
> traditional calendar) in the opening time syntax, if they're split up
> for "simplicity"? What about when the opening time also cover
> non-holiday festivals that only occurs according to either calendars?
>
> On 2019-05-18 Sat 04:50, Paul Allen  > wrote:
>
> Problem of splitting: what if a mapper gives the opening times in
> both calendar_X and calendar_Y
> and they disagree?  Consumers will have to have rules like: in
> country_Z use calendar_X if given,
> otherwise use standard opening_hours if given, otherwise use
> calendar_Y if given, otherwise
> pick at random from what is left.
>
> -- 
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Phake Nick]

That doesn't seems to solve the problem that would occur. For instance, how
to represent the first Sunday (a feature in Gregorian calendar) after
Chinese traditional ceremony X (a feature in Chinese traditional calendar)
in the opening time syntax, if they're split up for "simplicity"? What
about when the opening time also cover non-holiday festivals that only
occurs according to either calendars?

On 2019-05-18 Sat 04:50, Paul Allen  wrote:

> Problem of splitting: what if a mapper gives the opening times in both
> calendar_X and calendar_Y
> and they disagree?  Consumers will have to have rules like: in country_Z
> use calendar_X if given,
> otherwise use standard opening_hours if given, otherwise use calendar_Y if
> given, otherwise
> pick at random from what is left.
>
> --
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>
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Fri, 17 May 2019 at 21:19, Mateusz Konieczny 
wrote:

17 May 2019, 21:13 by pla16...@gmail.com:
>
> I think that you would have to come up with something like
> opening_house:islamic or
> something like that to segregate the two systems.
>
> I am not convinced that it would make it less messy - it just hides part
> of complexity by
> moving it to a different tag.
>

It  really would make it less messy.  It's not simply trying to sweep it
under the carpet.  Some of
what we already have is hard for humans to understand.  Which is why we
have syntax checkers,
but they have some disagreements in what they consider valid, so parsing it
is hard, too.  *Any*
proposed extension to the current syntax, however small, has to be very
carefully considered
in case it breaks things.  A large change such as throwing in a different
calendar is pretty
much guaranteed to be almost incomprehensible to humans and impossible to
parse.

Splitting it off into opening_hours:calendar minimises the problems caused
by handling other
calendars.  It doesn't make the syntax for standard opening_hours more
complex.  It also has
the very big advantage that if we later discover, or introduce, a serious
flaw in the syntax for
calendar_X it won't have an effect on calendar_Y.  "Ooops, we really
screwed up the Klingon
calendar, but at least all the other calendars are OK."  In other words,
open up this can of worms
if you must, but I don't want any on my plate.

Problem of splitting: what if a mapper gives the opening times in both
calendar_X and calendar_Y
and they disagree?  Consumers will have to have rules like: in country_Z
use calendar_X if given,
otherwise use standard opening_hours if given, otherwise use calendar_Y if
given, otherwise
pick at random from what is left.

-- 
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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Mateusz Konieczny]

17 May 2019, 21:13 by pla16...@gmail.com:

> On Fri, 17 May 2019 at 19:42, Saeed Hubaishan <> hubais...@outlook.sa 
> > > wrote:
>
>>
>> So opening_hours syntax must accept the other calendar systems. 
>>
>
> Opening_hours syntax is complicated enough, without adding other calendar 
> systems.  It
> is a compromise between human readability and computer parseability.  Some 
> would say it
> is already too complicated, even though it doesn't handle some things that 
> some people
> would like it to.
>
> I think that you would have to come up with something like 
> opening_house:islamic or
> something like that to segregate the two systems.
>
I am not convinced that it would make it less messy - it just hides part of 
complexity by 
moving it to a different tag.

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Re: [Tagging] Opening hours syntax for non Gregorian calendar

[Paul Allen]

On Fri, 17 May 2019 at 19:42, Saeed Hubaishan  wrote:

>
> So opening_hours syntax must accept the other calendar systems.
>

Opening_hours syntax is complicated enough, without adding other calendar
systems.  It
is a compromise between human readability and computer parseability.  Some
would say it
is already too complicated, even though it doesn't handle some things that
some people
would like it to.

I think that you would have to come up with something like
opening_house:islamic or
something like that to segregate the two systems.

And that only handles dates.  Some Islamic countries use solar time rather
than a time offset
from UTC.  Worse, different Islamic countries have slightly different
definitions of solar time.
And then some places may use the solar time (defined one way) of a central
location whilst
others use the solar time (possibly defined a different way) locally: one
country might use
solar time in the capital city everywhere in the country whilst another
uses the local solar time.
You can probably get away with saying "12:00 means noon in this locality,
however they define
it" but maybe not.  "However the locals define it" is probably workable for
tourists, not so good
for people who want to phone an office on the other side of the country
before it closes.

It gets messy, but if you can come up with something that handles all the
possibilities,
that's great.  But please put it in opening_hours: whatever_we_call_it
rather than ordinary
opening_hours.  Because opening_hours is already messy enough.

-- 
Paul
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